1. Field of the Invention
The present invention relates to a disk holding device and disk processor. More particularly, the present invention relates to a disk holding device for holding a disk and capable of reliably releasing the disk from holding, and a disk processor.
2. Description Related to the Prior Art
A disk processor is known and commercially marketed in the field of instruments for data recording. The disk processor includes a data writer for writing data to a great number of disks, such as CDs and DVDs, and also includes a label printer for printing a label on each of the disks. An unprocessed disk storage unit is included in the disk processor for stacking unprocessed disk. A disk holding device or disk holding arm takes up disks one after another. Each disk is moved to the data writer, transferred from the data writer to the label printer, and transferred from the label printer to a processed disk storage unit.
The disk holding device includes coupling levers or disk holding levers for holding a disk. There is a center hole in a disk. The coupling levers are entered in and engaged with the center hole for holding. There have been various suggested structures of the coupling levers for the purpose of exactly holding each one of disks in a discrete manner.
U.S. Pat. Pub. No. 2007/0267881 (corresponding to JP-A 2007-310920) discloses a set of three coupling levers insertable in the center hole of a disk for contacting an edge surface of the center hole. Among the coupling levers, two have a contact surface for contacting the edge surface of the center hole. The contact surface has a size greater than a thickness of the disk. A remaining one of the coupling levers has a contact surface for contacting the edge surface of the center hole, the contact surface has a size smaller than the thickness of the disk. This is for the purpose of avoiding simultaneous holding of two disks.
JP-A 2002-052488 discloses a disk holding structure including a stationary portion and the coupling levers. The stationary portion is entered in the center hole for contacting the edge surface thereof. Also, a first one of the coupling levers in a straight form contacts the edge surface of the center hole. An uppermost one of disks is held and moved up by the stationary portion and the first coupling lever. Then a second one of the coupling levers having a V-shaped end is inserted in the center hole, is shifted to push the edge surface of the center hole. Thus, the disk can be held in a stable manner.
While a disk is held, the coupling levers press the edge surface of the center hole. At least the first coupling lever, which has the size greater than the disk thickness, contacts a lower surface of the disk. If the first coupling lever is shifted in an inward direction to release holding, the disk is separated by its weight from a second one of the coupling levers without contacting the lower surface. However, the disk remains in contact with the second in a coupled state, so that the disk starts becoming skewed. Then the disk becomes disengaged from the second coupling lever in occurrence of the skew, and drops down in the skewed state. There arises a problem in failure of normally transferring into the processed disk storage unit.